Remote control devices for controlling television sets and other electronic equipment are well known. Such devices usually transmit a control signal in the infrared frequency spectrum over some distance to a receiver located within the controlled television set. The receiver converts the transmitted radiation into the control signal which controls predetermined operations of the television set.
Typically, a remote control device consists of a data entry key, processing circuitry, and a transmitter. The data entry key may be employed by a user to select a particular control signal to be transmitted, or to program the remote control device by means of the processing circuitry. For example, some remote control devices include push-button keypads as a means for entering data. The processing circuitry within a typical remote control receives input signals from the user by means of the entry key. These input signals are then processed to provide driving signals which drive the transmitter. In some advanced remote control devices, the processing circuitry may be implemented as a microprocessor chip and a memory chip. Commonly, remote control devices transmit control signals in the infrared frequency spectrum, since this frequency of radiation has been found to be an effective means of propagating signals through the air, and it is relatively simple to construct infrared transmitters.
Prior remote control devices have been equipped with an infrared diode, or the like, for transmitting control signals to infrared receivers within electrical apparatuses. The diode is usually mounted on one end of the remote control device so that infrared radiation is transmitted from the end on which the diode is mounted. Thus, in order to transmit a control signal to an electrical apparatus, the remote control device is pointed in the direction of the receiver within the electrical apparatus.
In such devices, it is important that the transmitting end of the remote control be accurately pointed towards the receiver of the electrical apparatus, otherwise, the intensity of the transmitted radiation may not be sufficient to assure proper reception of the control signals. In addition, it is important that no objects are situated in the line-of-sight between the transmitting remote control and the receiver, because such objects may prevent or interfere with the transmission of the control signal.